Want, omdat, dus or maar?

Each of these words joins two sentences, and each one decides the word order that follows.

• want (because), maar (but), en (and), of (or): normal order. Ik ben te laat, want de trein had vertraging.
• omdat (because): the verb goes to the end. Ik ben te laat, omdat de trein vertraging had.
• dus (so) and daarom (that's why): the verb comes right after them. Het regent, dus neem ik de bus.

Want and omdat mean the same, but only omdat can start a sentence: Omdat het regent, neem ik de bus. For a cause that nobody chose, such as a delay, doordat is also possible. After dus, normal order (dus ik neem de bus) is correct too.